The mass spectrum of an element X is shown below. Calculate the average atomic mass of X?

• 124.8 a.m.u

• 126.0 a.m.u

• 127.2 a.m.u

• 252 a.m.u

Calculate the mass of perchloric acid, HClO₄ needed to prepare 3.45 molal perchloric acid solution using 100 mL volumetric flask.

• 0.345 g

• 34.67 g

• 3.43 x 10^-3 g

• 34.67 x 10³ g

Hydrocarbon E consists of 82.66% carbon and 17.34% hydrogen with a molar mass of 58.1 g/mol. Determine the molecular formula of E.

• C₂H₅

• C₂H₆

• C₄H₁₀

• C₄H₁₂

A solution of hydrochloric acid with 37.8% by mass of HCl has a density of 1.19 g/cm³. Calculate the molarity of concentrated hydrochloric acid.

• 1.04 M

• 1.23 M

• 10.4 M

• 12.3 M

• 1

• 2

• 4

• 8

• 4.453

• 4.771

• 44.53

• 4771

Determine which molecule has dipole moment, μ = 0.

• CS₂

• SO₂

• NO

• H₂O

Choose the most plausible Lewis structure for CNO^-.

• A

• B

• C

• D

Arrange the following compounds in the order of increasing boiling point.

HF, HCl, Cl₂

• HCl < HF < Cl₂

• HCl < Cl₂ < HF

• HF < HCl < Cl₂

• Cl₂ < HCl < HF

The hybridization of the central atom in the following molecules is sp³ except

• NH₃

• H₂O

• ClF₃

• CH₃Cl